Mobile telecommunications system transmission and reception points and methods

ABSTRACT

A mobile telecommunications system transmission and reception point has circuitry configured to receive a status indicator, and to switch between an active state and an inactive state in response to the received status indicator.

TECHNICAL FIELD

The present disclosure generally pertains to mobile telecommunicationssystem transmission and reception points and mobile telecommunicationsystems methods.

TECHNICAL BACKGROUND

Several generations of mobile telecommunications systems are known, e.g.the third generation (“3G”), which is based on the International MobileTelecommunications-2000 (IMT-2000) specifications, the fourth generation(“4G”), which provides capabilities as defined in the InternationalMobile Telecommunications-Advanced Standard (IMT-Advanced Standard), andthe current fifth generation (“5G”), which is under development andwhich might be put into practice in the year 2020.

A candidate for providing the requirements of 5G is the so-called LongTerm Evolution (“LTE”), which is a wireless communications technologyallowing high-speed data communications for mobile phones and dataterminals and which is already used for 4G mobile telecommunicationssystems. Other candidates for meeting the 5G requirements are termed NewRadio Access Telecommunications Systems (NR). An NR can be based on LTEtechnology, just as LTE was based on previous generations of mobilecommunication technology.

LTE is based on the GSM/EDGE (“Global System for MobileCommunications”/“Enhanced Data rates for GSM Evolution” also calledEGPRS) of the second generation (“2G”) and UMTS/HSPA (“Universal MobileTelecommunications System”/“High Speed Packet Access”) of the thirdgeneration (“3G”) network technologies.

LTE is standardized under the control of 3GPP (“3rd GenerationPartnership Project”) and there exists a successor LTE-A (LTE Advanced)allowing higher data rates than the basic LTE and which is alsostandardized under the control of 3GPP.

For the future, 3GPP plans to further develop LTE-A such that it will beable to fulfill the technical requirements of 5G.

As the 5G system will be based on LTE or LTE-A, respectively, it isassumed that specific requirements of the 5G technologies will,basically, be dealt with by features and methods which are alreadydefined in the LTE and LTE-A standard documentation.

Moreover, in 3GPP document RP-160671, “New SID Proposal: Study on NewRadio access Technology”, NTT DOCVOMO, Ran #71, a Study Item on NewRadio Access Technology (NR) has been agreed upon. Subject of this StudyItem is to study and to develop a new Radio Access Technology (RAT) forthe next generation wireless communication system, e.g. 5G. The new RATis expected to operate in a large range of frequencies, from hundreds ofMHz to 100 GHz and it is expected to cover a broad range of use cases.The use cases that are considered under this Study Item are EnhancedMobile Broadband (eMBB), Massive Machine Type Communications (mMTC) andUltra Reliable & Low Latency Communications (URLLC).

In addition to the large range of services, the NR is also expected tobe deployed in different environments, wherein an example of such adeployment is for a high speed train, as discussed in 3GPP documentR1-163867, “Updated summary of evaluation assumptions for NR”, CMCC,RAN1#84bis, where the UE is expected to support a speed of up to 500kmph. The operating carrier frequencies for high speed trains in NRbeing considered are 4 GHz and 30 GHz.

Although there exist techniques for provide signaling for moving userequipments, it is generally desirable to improve the existingtechniques.

SUMMARY

According to a first aspect, the disclosure provides a mobiletelecommunications system transmission and reception point comprisingcircuitry configured to receive a status indicator; and switch betweenan active state and an inactive state in response to the received statusindicator.

According to a second aspect, the disclosure provides a mobiletelecommunications system transmission and reception point comprisingcircuitry configured to transmit a status indicator for switchinganother transmission and reception point between an active state and aninactive state.

According to a third aspect, the disclosure provides a mobiletelecommunications system base station comprising multiple remote radioheads and circuitry configured to receive a status indicator; anddeactivate selectively the multiple remote radio heads based on thereceived status indicator.

According to a fourth aspect, the disclosure provides a mobiletelecommunications system method comprising obtaining neighbor cellinformation including priority information of neighboring cells to bemeasured; and measuring cells based on the priority information.

According to a fifth aspect, the disclosure provides a mobiletelecommunications system method for a transmission and reception pointserving a user equipment, comprising obtaining a speed related parameterof the served user equipment; and compensating for a Doppler effect in awireless link communication to the served user equipment, based on theobtained speed related parameter.

According to a sixth aspect, the disclosure provides a mobiletelecommunications system method for a user equipment served by atransmission and reception point, comprising receiving a speed relatedparameter of the served user equipment from the transmission andreception point; and compensating for a Doppler effect in a wirelesslink communication to the transmission and reception point, based on theobtained speed related parameter.

Further aspects are set forth in the dependent claims, the followingdescription and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are explained by way of example with respect to theaccompanying drawings, in which:

FIG. 1 illustrates a radio access network and a train on a track;

FIG. 2 illustrates signaling of a status indicator in the network ofFIG. 1;

FIG. 3 illustrates train movement in the network of FIG. 1;

FIG. 4 illustrates eNodeBs with multiple remote radio heads;

FIG. 5 illustrates a mobile telecommunications system method;

FIG. 6 illustrates a Doppler Effect in the network of FIG. 1;

FIG. 7 illustrates a change of a Doppler Effect of a moving train;

FIG. 8 illustrates the Doppler Effect for two user equipments passing atransmission and reception point;

FIG. 9 illustrates the Doppler Effect of a train starting from a trainstation;

FIG. 10 illustrates a mobile telecommunications system method;

FIG. 11 illustrates a mobile telecommunications system method; and

FIG. 12 schematically illustrates a computer which can implement atransmission and reception point, user equipment, base station or othercomponents described in this disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Before a detailed description of the embodiments under reference of FIG.1, general explanations are given.

As mentioned in the outset, several generations of mobiletelecommunications systems are known, e.g. the third generation (“3G”),which is based on the International Mobile Telecommunications-2000(IMT-2000) specifications, the fourth generation (“4G”), which providescapabilities as defined in the International MobileTelecommunications-Advanced Standard (IMT-Advanced Standard), and thecurrent fifth generation (“5G”), which is under development and whichmight be put into practice in the year 2020.

A candidate, in some embodiments, for providing the requirements of 5Gis the so-called Long Term Evolution (“LTE”), which is a wirelesscommunications technology allowing high-speed data communications formobile phones and data terminals and which is already used for 4G mobiletelecommunications systems. Other candidates for meeting the 5Grequirements are termed New Radio Access Telecommunications Systems(NR). An NR can be based on LTE technology, just as LTE was based onprevious generations of mobile communication technology.

LTE is based on the GSM/EDGE (“Global System for MobileCommunications”/“Enhanced Data rates for GSM Evolution” also calledEGPRS) of the second generation (“2G”) and UMTS/HSPA (“Universal MobileTelecommunications System”/“High Speed Packet Access”) of the thirdgeneration (“3G”) network technologies.

LTE is standardized under the control of 3GPP (“3rd GenerationPartnership Project”) and there exists a successor LTE-A (LTE Advanced)allowing higher data rates than the basic LTE and which is alsostandardized under the control of 3GPP.

For the future, 3GPP plans to further develop LTE-A such that it will beable to fulfill the technical requirements of 5G.

As the 5G system will be based on LTE or LTE-A, respectively, it isassumed that specific requirements of the 5G technologies will,basically, be dealt with by features and methods which are alreadydefined in the LTE and LTE-A standard documentation in some embodiments.

Moreover, in 3GPP document RP-160671, “New SID Proposal: Study on NewRadio access Technology”, NTT DOCVOMO, Ran #71, a Study Item on NewRadio Access Technology (NR) has been agreed upon. Subject of this StudyItem is to study and to develop a new Radio Access Technology (RAT) forthe next generation wireless communication system, e.g. 5G. The new RATis expected to operate in a large range of frequencies, from hundreds ofMHz to 100 GHz and it is expected to cover a broad range of use cases.The use cases that are considered under this Study Item are EnhancedMobile Broadband (eMBB), Massive Machine Type Communications (mMTC) andUltra Reliable & Low Latency Communications (URLLC).

In addition to the large range of services, the NR is also expected tobe deployed in different environments, wherein an example of such adeployment is for a high speed train, as discussed in 3GPP documentR1-163867, “Updated summary of evaluation assumptions for NR”, CMCC,RAN1#84bis, where the UE is expected to support a speed of up to 500kmph. The operating carrier frequencies for high speed trains in NRbeing considered are 4 GHz and 30 GHz.

A general setup, which is used in some embodiments, is illustrated inFIG. 1.

A 5G Radio Access Network (RAN) has multiple Transmission and ReceptionPoints (TRP) 2 a-f or base stations 2 a-f, which are deployed along arailway track 3 to provide a line-of-sight (LOS) coverage for a train 4.In some embodiments, a base station comprises one or more TRPs.

In the exemplary embodiment of FIG. 1, at each end of the train 4, arespective UE 5 a (left side in FIG. 1) and 5 b (right side in FIG. 1)is provided such that the train speed and the speed of the UEs 5 a and 5b are identical.

Antennas of the TRPs 2 a-f may be directed towards the railway track 3with the aim of providing maximum coverage for the train 4 and UEs 5 aand 5 b mounted on the train. Due to the direction towards the railwaytrack 3, it is unlikely, in some embodiments, that such TRPs 2 a-f serveUEs which are not travelling along the railway track 3, such aspedestrians outside of the railway track.

Since a TRP 2 a-f would typically serve the train 4 only for a shorttime period, especially for high speed trains, it has been recognizedthat the TRP needs to only be active for a short time period and itwould be a waste of energy to keep such a TRP active when there is notrain passing through its coverage. Hence, some embodiments provide anenergy efficient way of operating such TRPs.

Consequently, some embodiments pertain to a mobile telecommunicationssystem transmission and reception point (TRP) comprising circuitryconfigured to receive a status indicator; and switch between an activestate and an inactive state in response to the received statusindicator.

As mentioned, the mobile telecommunications system may be a 5G, e.g.LTE-A or NR, mobile telecommunication system or the like.

The TRP may be included in a base station, such as an eNodeB or thelike, it may be part of a base station or it may be a base station. Insome embodiments, a base station may include multiple TRPs.

The status indicator includes at least one of and/or may be indicativeof at least one of: a command to switch between an inactive or activestate, connection state information, information about a completedhandover procedure, end of vehicle information, train speed or the like.

In some embodiments, the TRP serves one or more user equipments, whichare mounted on a vehicle, such as a train and as also discussed aboveunder reference of FIG. 1.

The user equipment may be a mobile phone, a smartphone, computer,tablet, tablet personal computer or the like including a mobilecommunication interface, or any other device which is able to perform amobile telecommunication via, for example, LTE(-A), such as a hot spotdevice with a mobile communication interface.

In some embodiments, the active state includes functions of at least oneof receiving and transmitting data, e.g. from and to a user equipment.The inactive state may include at least one of discontinuous receptionmode and discontinuous transmission mode. The inactive state may includeturning off at least one of a transmitter and receiver of the TRP.

The circuitry may be further configured to transmit a status indicator.

The circuitry may be further configured to switch into the inactivestate after a predetermined time.

Some embodiments pertain to a mobile telecommunications systemtransmission and reception point comprising circuitry configured totransmit a status indicator for switching another transmission andreception point between an active state and an inactive state.

The circuitry may be further configured to transmit the status indicatorto a neighboring transmission and reception point.

The circuitry may be further configured to detect a mobility of a userequipment, the user equipment being mounted to a vehicle, such as atrain, as discussed above.

The circuitry is further configured to detect a movement direction ofthe vehicle and, thus, e.g. of equipment mounted to the vehicle.Thereby, the status indicator can be transmitted along the movementdirection of the vehicle.

The one or more other transmission and reception points may beneighboring to the mobile telecommunications system transmission andreception point, such that the one more other transmission and receptionpoints may be in the direction of travel of the vehicle.

The status indicator may be transmitted to a number of othertransmission and reception points, and the number of the othertransmission and reception points may depend on the velocity of thevehicle. In some embodiments, the number of other transmission andreception points may also depend on the direction of travel of thevehicle.

Some embodiments pertain to a mobile telecommunications system basestation comprising multiple remote radio heads and circuitry configuredto receive a status indicator and deactivate (and/or activate)selectively the multiple remote radio heads based on the received statusindicator.

The status indicator may be received from a neighboring base station, asalso mentioned above.

The deactivation of the multiple remote radio heads may be further basedon a geographical relationship to the neighboring base station. Forexample, closer remote radio heads may be deactivated while remote radioheads which are farther away stay active.

The status indicator may indicate a last activated remote radio head ofthe neighboring base station. Thereby it can be determined whether andwhich remote radio heads of the present base station may be activated.

The outermost remote radio heads of a base station may stay in theactive state. Thereby, for example, a seamless handover to remote radioheads of a neighboring base station can be performed.

The circuitry of the present base station or another base station may befurther configured to detect an active remote radio head, based on asignal measurement. The signal measurement may include at least one of:receiving uplink signals, sounding reference signals, physical uplinkshared channel, ACK/NACK feedback signaling. The deactivation of themultiple remote radio heads may be further based on the signalmeasurement. The signal measurement may be performed by a user equipmentand, for example, the result may be transmitted to the base station,e.g. in the case where the base station transmits downlink signals, suchas reference signals or synchronization signals. In the case that theuser equipment transmits the signals mentioned above (i.e. uplinksignals, sounding reference signals, etc.), the base station may receivethe signals and perform the measurement. Hence, in some embodiments, theremote radio heads of the present base station may be activated ordeactivated either by the base station itself or by another base stationwhich performed or received the signal measurements and detected activeradio remote heads on the another base station.

The remote radio heads may be uniquely identifiable. Thereby, eachremote radio head may be deactivated and activated selectively andseparately from other radio remote heads.

Returning to FIG. 2, there is the RAN 1 of FIG. 1 illustrated, whereinthe train 4 travels from left to right in FIG. 2 (see also arrowdepicted on train 4).

In this embodiment, an active state and an inactive state are definedfor the TRPs 2 a-f.

As discussed above, a status indicator, e.g. an activate indicator, isintroduced, which is sent from an active state TRP to one or moreinactive state TRP(s) such that these TRPs transit from inactive toactive state. This is illustrated in FIG. 2. The TRP 2 a is in an activestate and transmits the status indicator to TRPs 2 b and 2 c, which arein an inactive state (see also arrows from TRP 2 a to TRPs 2 b and 2 c).

In the present embodiment, the mobility is determined, such as thedirection of the UEs 5 a and 5 b, wherein the UEs 5 a and 5 b may belocated in the train or they may act as a relay attached to the outsideof the train. The direction of the train 4 and, thus, of UEs 5 a and 5b, can be predicted, since the train 4 has to travel along the railwaytrack 3.

Hence, TRP 2 a, which is in the active state and serves the UEs 5 a and5 b of the train 4, knows the direction of travel of the train 4, andthus sends the status/activate indicator to the next two TRPs 2 b and 2c, which are located in the movement direction of the train 4, and thus,of UEs 5 a and 5 b. Thereby, i.e. upon receipt of the status indicator,these neighboring TRPs 2 a and 2 b transit or switch from the inactiveto the active state so that they are ready to serve the UEs 5 a and 5 bof the incoming train 4.

In the present embodiment, the first TRP 2 a also knows the speed of thetrain 4 and it uses the speed to determine the number of neighbor TRPswhich need to be activated to provide smooth coverage for the train 4.

In contrast to this embodiment, the UE mobility is more difficult topredict in a coverage of an urban/suburban area and in cases where theUE distribution is not within a fixed known location, as is the case forthe embodiment of FIGS. 1 and 2.

As mentioned above, in the present embodiment, in the active state theTRP is transmitting and/or receiving and in the inactive state the TRPis in a DRX and/or DTX mode.

In another embodiment, in the inactive state the TRP transmitter and/orreceiver are turned off, For example, a fronthaul transmitter providingan interface from the network to the UEs is turned off, while thebackhaul, along which “status/activate indicators” are transmitted andwhich includes other interfaces, is still active. As is generally known,the TRPs or base stations are connected to each other via the backhauland the status/activate indicator can be transmitted over the backhaulconnection between the TRPs.

Moreover, an active TRP can transit or switch back into an inactivestate if it does not detect any traffic, e.g. UE or train, within apredefined period of time or it switches back upon receipt of a statusindication including a deactivate indication, e.g. from the network, forexample, from another TRP. For example, once the UE 5 b has connected tothe TRP 2 b in FIG. 2, TRP 2 b can send a status indicator includingdeactivate indication to TRP 2 a.

In another embodiment, an active TRP, e.g. a first TRP, sends statusindicator(s) to other TRPs, e.g. a second TRP, in order to indicate thatit has connected with the train 4 and the UEs 5 a and 5 b, respectively.For example, referring to FIG. 2, TRP 2 a can send status indicationsincluding activation indicators to TRPs 2 b and 2 c. Once the train 4(UEs 5 a and 5 b respectively) connects to the TRP 2 c, the TRP 2 csends a status indicator including a “connection indication” to thefirst TRP 2 a. Once TRP 2 a receives the status indicator including theconnection indication, the TRP 2 a switches into the inactive state.

In another embodiment, a TRP moves to an inactive state once it hashanded over a UE belonging to the train to another TRP.

For example, referring to FIG. 2, TRP 2 a sends status indicationsincluding activation commands to TRPs 2 b and 2 c. The UE(s), e.g. UEs 5a and/or 5 b on the train perform handover measurements. Once, forexample, the UE 5 a performs a handover measurement with significantquality, TRP 2 a performs a handover of the UE 5 a to the TRP 2 b. Oncethis handover is complete, this is known to TRP 2 a since it receives amessage (e.g. status indicator) from TRP 2 b indicating that the UEcontext of UE 5 a has been transferred to TRP 2 b. For example, TRP 2 bcan send a “UE Context Release” message (status indicator) to TRP 2 a,wherein TRP 2 a returns/switches to the inactive state upon receipt ofthe “UE Context Release” message.

It will be understood that in some embodiments, an implementation may bemore complex than described above. For example, on a congestedrailtrack, TRP 2 c may indicate to TRP 2 b that it can move to aninactive state, e.g. in accordance with one of the embodiments discussedabove, but TRP 2 b might have been informed by TRP 2 a that it needs toswitch into an active state due to a following train. In this case, theTRPs may implement an algorithm that prioritizes being in an activestate over returning to an inactive state.

In another embodiment, which is explained under reference of FIG. 3, an“End of Train” indicator (status indicator) is sent by a relay UE 6 atthe last carriage of the train 4 to the serving TRP 2 a (the setup ofthe RAN 1 corresponds to the RAN 1 of FIGS. 1 and 2 explained above).The status indicator (end of train indicator) indicates that thereceiving TRP, i.e. TRP 2 a in the present example, can switch to theinactive state.

In some embodiments, upon receipt of a status indicator such as the endof train indicator, a timer for switching to the inactive state can bestarted or it is switched to the inactive state if additionally, areported measured (Downlink) signal goes below a threshold.

As can be taken from FIG. 3, the relay UE 6, which is attached to theend of the last carriage of the train 4, transmits the “End of Train”indicator when it passes the TRP 2 a, e.g. when its measured downlinksignal is below a threshold. This will aid the active TRP(s), i.e. TRP 2a, to determine when to switch to the inactive state. Alternatively, theUE 6 at the end of the train 4 will continually transmit an “end oftrain” indicator and when the connection to that UE 6 is lost or itssignal quality falls below a certain level (e.g. as measure by an activeTRP, such as TRP 2 a), an active TRP, such as TRP 2 a, can determinethat it shall switch to the inactive state.

In some embodiments, TRPs which are close to a train station or otherlocation, where, for example, multiple trains pass by, can bepermanently active (or active most of the time). When the TRP detects anincoming train (or UE), it will send status indicator including ActivateIndications, as discussed above, to its neighboring inactive TRPs in thedirection of travel of the train. In some embodiments, an active TRP hasan updated list of neighboring TRPs that are active or inactive andhence it only needs to send the status indicators, e.g. ActivateIndicator, to inactive TRPs.

The status indicators, e.g. Activate Indicator, are only sent to TRPsthat are in the direction of travel (in a forwards sense) of the train.

In another embodiment, the status indicator, such as the ActivateIndicator, is sent from a server rather than directly from anotheractive TRP. For example in FIG. 2 or 3, when TRP 2 a is active, it canindicate to a server the direction and speed of the train 4 and theserver decides which other TRPs shall be activated and transmits to thema respective status indicator over the backhaul.

In another embodiment, the status indicator, such as the ActivateIndicator, is sent from a network element that connects network elementsat a lower level of hierarchy. For example, the status indicator, suchas the Activate Indicator, is sent from a Mobility Management Entity(MME) to eNodeBs (acting as TRPs) that are connected to the MME. Inanother example, related to the 3G architecture, the Activate Indicatoris sent from an RNC to a NodeB that is connected to the RNC.

As discussed, the TRP discussed above can either be a base station, e.g.having a functionality equivalent to an LTE eNodeB, it can be part of abase station or it can also be a remote radio head (RRH).

An RRH may have at least one of the following architectures:

A set of antennas and amplifiers (in the transmit and receivedirections) that are linked via a backhaul to a baseband processingunit; and/or

antennas, amplifiers and baseband processing units that are linked via abackhaul to a processing unit (where the “processing unit” performs suchfunctions as scheduling, MAC processing, transport channel processingetc. (noting that the layer 1 processing can be split between physicalchannel processing functions and transport channel processing functions:the physical channel processing functions can be performed at the RRHand the transport channel processing functions can be performed in theprocessing unit)).

In some embodiments, as will discussed under reference of FIG. 4 in thefollowing, the TRPs are RRHs connected to the eNodeB. In brief, theeNodeB turns the RRHs on and off that are under the control of theeNodeB (via an “intra-eNodeB Activate Indicator”, which can be a statusindicator as described herein). When a train reaches the last RRHs thatare controlled by an eNodeB, the source eNodeB can send an ActivateIndicator to the next eNodeB along the railtrack (the target eNodeB).The Activate Indicator can indicate which RRHs attached to the sourceeNodeB were the last active RRHs. This can help the target eNodeB todetermine which RRHs to activate under its control.

FIG. 4 illustrates a first base station eNodeB_A and a second basestation eNodeB_B.

The eNodeB_A has seven RRHs, namely RRH_A1 to RRH_A7, connected to itand the eNodeB_B has six RRHs connected to it, namely RRH_B1 to RRH_B6.

The eNodeB_A and eNodeB_B are located along two tracks 3 a and 3 b,which have a rail junction 3 c. The two eNodeBs and their associatedRRHs cover the area of the rail junction 3 c.

For a train travelling in the direction from X to Y, the eNodeB_A sendsstatus/activate indicators (“intra-eNodeB activate indicators”)sequentially to the RRHs along the direction the train travels pastRRH_A1, RRH_A2, RRH_A3, RRH_A6, and RRH_A7. As the train passes RRH_A7,eNodeB_A sends an Activate Indicator (and “inter-eNodeB activateindicator”) to the eNodeB_B.

In the following, several scenarios are discussed:

In a first scenario, the eNodeB_A has knowledge of the RRH locations ofRRH_B1 to RRH_B6 of the eNodeB_B and in the Activate Indicator sent tothe eNodeB_B, the eNodeB_A indicates that RRH_B1 should be activated,which is the next RRH in the travel direction of the train after RRH_A7.

In a second scenario, the eNodeB_B has knowledge of the RRH locationsRRH_A1 to RRH_A7 of eNodeB_A and the eNodeB_A sends an ActivateIndicator that states that the RRH currently in use by eNodeB_A isRRH_A7. As the eNodeB_B knows the locations of the RRHs of the eNodeB_A,the eNodeB_B can determine that the following RRH after RRH_A7 is RRH_B1and thus, eNodeB_B activates RRH_B1, which is the RRH which is locatedclosest to RRH_A7 of eNodeB_A.

In a third scenario, there is no mutual knowledge about the RRHlocations between eNodeB_A and eNodeB_B, but the eNodeBs know theirrelative geographic locations, e.g. the relative geographic locations ofthe eNodeBs with respect to each other. In this case, when eNodeB_Asends an Activate Indicator to the eNodeB_B, the eNodeB_B activates allof its connected RRHs that are close to the eNodeB_A, i.e. in theexample of FIG. 4, the eNodeB_B activates RRH_B1 and RRH_B4. Moreover,the eNodeB_B can deactivate one of RRH_B1 or RRH_B4 once a train passesthe other RRH, e.g. if a train passes RRH_B1, a deactivation message canbe sent to RRH_B4 and vice versa.

Moreover, in an embodiment, when an eNodeB controls multiple RRHs, theRRHs at the geographic limits of the eNodeB are always active and theeNodeB activates/deactivates only the inner RRHs. Hence, the outer RRHsare always active to allow for trains handing over from eNodeB toeNodeB, but the inner RRHs can be activated/deactivated to save energy.

Based on the example of FIG. 4 this means:

For eNodeB_A, RRH_A1, RRH_A5 and RRH_A7 are always active, whereasRRH_A2, RRH_A3, RRH_A4 and RRH_A6 can be activated/deactivated asdiscussed. For eNodeB_B, RRH_B1, RRH_B4, RRH_B3 and RRH_B6 are alwaysactive, whereas RRH_B2 and RRH_B5 can be activated/deactivated

This embodiment allows to simplify handover signaling between theeNodeBs while still allowing energy saving.

In the above embodiments pertaining to RRHs, it may also be implementedthat the eNodeB can determine which RRHs are currently active based onsignal quality measurements from the RRHs. For example, the UE (on thetrain) may transmit uplink (UL) signals, such as sounding referencesignals (SRS), physical uplink shared channel (PUSCH) and/or ACK/NACKfeedback signaling (e.g. carried on a Physical Uplink Control Channel:PUCCH). The RRH can perform signal quality measurements related to theseUL signals and send them to the eNodeB. The eNodeB may then comparethese quality measurements to determine which RRHs should be activatedand deactivated.

In another embodiment, the quality measurements are determined by the UE(based on downlink signals) and reported back to the eNodeB. E.g.signals from the RRHs are uniquely identifiable (e.g. reference signals,such as cell-specific reference signals (CRS) or channel stateinformation reference signals (CSI-RS), from one RRH are different tothe reference signals from another RRH: the reference signals can betransmitted from a different antenna port, or be scrambled with adifferent code). Based on the feedback signals from the UE (e.g.transmitted via channel state information, CSI, or RRC measurementreports), the eNodeB can determine which RRHs are to be activated andwhich are to be deactivated.

In some embodiments, not all TRPs respond to status indicators, such asActivate Indicators. For example, some TRPs serve both trains andsignaling or other safety equipment. Those TRPs that servesignaling/safety equipment may remain permanently active and henceignore any Activate Indicators that tell it to deactivate.

Some embodiments pertain to a mobile telecommunications system method,which is discussed in the following also under reference of FIG. 5 andwhich is applicable, for example, to the RAN of FIGS. 1 to 4. Beforediscussing the embodiment of FIG. 5, general explanations are given.

In some embodiments, a mobile telecommunications system method comprisesobtaining (e.g. receiving or generating) neighbor cell informationincluding priority information of neighboring cells to be measured; andmeasuring cells based on the priority information. The neighboring cellsmay be located along a direction of a travelling vehicle, e.g. a train,as also discussed above. The neighboring cell information may beindicative of cells for vehicles having different travel directions. Theneighboring cell information may be separated for vehicles havingdifferent travel directions. The neighboring cell information may beupdated based on the travelling direction. The neighboring cellinformation may be obtained by a neighboring cell measurement, which maybe performed by a user equipment.

Returning to FIG. 5, a train travelling at a speed of 500 kmph in a cellwith a diameter of 1 km will pass through the cell in 7 seconds, e.g. inthe RAN 1 of FIGS. 1 to 4 of the present disclosure. The handoverprocess, which has also been discussed above, may take some time, andhence, in some embodiments, there is a need to optimize how the UE onthe train performs neighbor cell measurements (for the purposes ofhandover). In addition, based on the above description (of how TRPs canbe activated and deactivated), some TRPs may be deactivated, and thus,it may be a waste of time for the UE to perform measurements on thosecells where the TRPs are activated.

In the embodiment of FIG. 5, the mobile telecommunications method 20 mayimprove the neighbor cell measurement process.

In this embodiment, neighbor cell list information, e.g. a neighbor celllist, is implemented, according to which neighbor cells within theneighbor cell lists each have a priority associated with them.

Such neighbor cell information is obtained at 21 in FIG. 5. In someembodiments, the neighbor cells within the neighbor cell lists arelisted separately for trains travelling in different directions. Forexample, for a single track traversing the cell (e.g. in an east-westdirection), separate neighbor cells are listed for trains travelling inan eastwards direction and for trains travelling in a westwardsdirection. More generally, there may be multiple rail routes crossingthe cell and the neighbor cell lists may indicate the priority ofneighbor cell measurements for each rail route.

At 22, the cells are measured, e.g. by a user equipment (e.g. UE 5 a or5 b discussed above), based on the priority information included in theneighbor cell list, i.e. the UE measures the neighbor cells in the orderof priority in the neighbor cell list (e.g. the neighbor cell list isranked in priority order).

At 23, the neighbor cell lists are updated dynamically based on thedirection in which trains are travelling. For example, for trainstravelling in a westwards direction, the neighbor cell lists are updatedto only include neighbor cells west of the approaching train andneighbor cells east of the train are either irrelevant to thewestward-bound train or have previously been deactivated, as has alsobeen discussed for the embodiments of FIGS. 1 to 4.

In an embodiment, the UE itself prioritizes the cells that it performsneighbor cell measurements on, such that the UE itself obtains theneighbor cell information including priority information of neighboringcells to be measured. For instance, the UE on the train (e.g. UE 5 a or5 b on train 4, as discussed above) performs measurements on neighborcells that it has not previously passed in preference to neighbor cellsthat it has previously passed.

In some embodiments, related to performing neighbor cell measurements, aprior-art UE may increase the frequency of neighbor cell measurementsthat it performs when the signal quality of the measurements drops belowa threshold. In some embodiments, e.g. for a high speed train, the UEcan quickly traverse from areas of good signal coverage to areas of poorsignal coverage. Hence, when the UE is travelling at a high speed, insome embodiments, the UE always performs neighbor cell measurements at ahigh rate and does not change the rate of neighbor cell measurements asa function of measured signal quality.

In UMTS, the RNC can send a 1 bit power saving indicator to the basestation, e.g. NodeB (NB). However, this indicator is not a specificcommand to turn the NB off, since the UMTS NB is not designed to beturned off. This indicator is initiated by the RNC without any specifiedcause. In contrast to this, in some of the embodiments discussed above,the status indictor, such as the Activate Indicator, is a specificcommand to (de)activate a known inactive/active TRP and it is initiateddirectly or indirectly by an active NB upon detection of incomingtraffic.

In a 3GPP Study Item on small cells (see exemplary TR36.872, “Small cellenhancement for E-UTRA and E-UTRAN—Physical Layer aspects” (Release 12),ETSI), there was a proposal to semi-statically turn on/off a small cellbased on traffic load. According to this proposal, a turned-off smallcell may be turned on if the traffic load in a neighborhood of the cell(including the cell itself) increases to a certain level. Conversely, aturned-on small cell may be turned off if the traffic load in aneighborhood of the cell decreases to a certain level. A small cell istypically deployed as hot spot with an overlaid macro cell (i.e. aHetNet deployment) and hence the small cell would be used to relieve thetraffic load of the macro cell. In such a scenario, the direction of theUE is not taken into account. In contrast to this, according to someembodiments discussed herein, the direction of travel of the UE is themain reason for turning on an adjacent TRP.

In the following, embodiments are discussed taking the known DopplerEffect into account.

Doppler is a function of the relative speed between receiver andtransmitter and hence a consequence of deploying the TRPs along therailway line is that it would cause very high Doppler between the TRPand the train, especially if the train is moving towards or away from aTRP as shown in FIG. 1 discussed above, where the train 4 travels fromleft to right, and, for example, UE 5 b moves towards TRP 2 d and awayfrom TRP 2 c.

In LTE the UE is expected to tolerate a frequency error of no more than750 Hz or 5% of the subcarrier spacing (15 kHz) for high speed trains(see exemplary in TS36.101, “3GPP: E_UTRA UE Radio Transmission &Reception (Release 13)”, v13.3.0).

If one assumes a 100 Hz frequency offset error at the UE, then themaximum Doppler is about 650 Hz. In contrast, the expected high speedtrain deployment for NR has a Doppler of 1851 Hz and 13,888 Hz at 4 GHzand 30 GHz, respectively, which are significantly higher than that ofLTE. In order to operate at such high Doppler, a higher density ofReference Signals (e.g. a RS at every symbol) and wider subcarrierspacing might be required (so that these high Dopplers are less than 5%of subcarrier spacing). It has been recognized that a wide subcarrierspacing would lead to a short symbol duration. Whilst a short symbolduration may be acceptable for a high complexity UE, it is notacceptable for low complexity devices, such as MTC devices, since itwould require high processing speed to process the shorter symbols,which may not be practical in such MTC devices.

Consequently, some embodiments pertain to mobile telecommunicationssystem methods which may allow low cost devices to operate at highDoppler speeds in a high speed vehicle or train scenario.

Some embodiments pertain to a mobile telecommunications system methodfor a transmission and reception point serving a user equipment,comprising obtaining a speed related parameter of the served userequipment; and compensating for a Doppler effect in a wireless linkcommunication to the served user equipment, based on the obtained speedrelated parameter. The speed related parameter may be indicative of aDoppler effect. The speed related parameter may be indicative of amaximum speed of the user equipment, wherein the maximum speed may bethe maximum speed between a transmission and reception point and theserved user equipment. The speed related parameter may be an indicatorof an average Doppler frequency shift. The method may further includetransmitting the speed related parameter of the served user equipment toat least one neighboring transmission and reception point. It mayfurther include determining a current speed of the served userequipment. The compensation may be further based on the current speed,wherein the current speed may be determined based on a measurementperformed by the user equipment. The current speed may be determinedbased on a radio measurement between the user equipment and the servingtransmission and reception point. The current speed may be determinedbased on a location information. The transmission and reception pointmay be configured to communicate in a forward and backward directionalong a movement direction of the served user equipment. Thetransmission and reception point may be configured to communicate in onedirection along a movement direction of the served user equipment. Afirst user equipment may be located at a first section of a vehicle anda second user equipment may be located at a second section of thevehicle, wherein the first section and the second section are distantfrom each other. The compensation for the Doppler Effect may includecompensation for the Doppler Effect in a wireless link communication tothe first and second served user equipments. The method may furtherinclude assigning first frequency resources to the first user equipmentand assigning second frequency resources to the second user equipment,wherein the first and second frequency resources are Doppler Effectcompensated. The method may further include assigning first timeresources to the first user equipment and assigning second timeresources to the second user equipment, wherein the first and secondtime resources are Doppler Effect compensated. The method may furtherinclude segmenting a carrier into a first component carrier assigned tothe first user equipment and segmenting the carrier into a secondcomponent carrier assigned to the second user equipment. The method mayfurther include transmitting the speed related parameter of the serveduser equipment to a neighboring transmission and reception point, basedon a frequency shift threshold value. The method may further includetransmitting the speed related parameter to the served user equipment.

Some embodiments pertain to a mobile telecommunications system methodfor a user equipment served by a transmission and reception point,comprising receiving a speed related parameter of the served userequipment form the transmission and reception point; and compensatingfor a Doppler effect in a wireless link communication to thetransmission and reception point, based on the obtained speed relatedparameter.

In some embodiments, a serving TRP signals one or more speed relatedparameters of UEs attached to (or inside) of a vehicle, e.g. high speedtrain, to its neighboring TRPs. For instance, the TRPs are part of RAN1, as has also been discussed above, for example, in association withFIGS. 1 to 4. The neighboring TRPs would then use these speed relatedparameters to compensate for the high Doppler experienced by the UE inthe high speed train when these TRPs serve these UEs. For example, ifthe actual Doppler experienced by the UE is f_(D) and using the saidparameters, the neighboring TRP obtained a compensation Doppler off_(C), the neighboring TRP would transmit its signal to the UE byoffsetting the frequency by −f_(C) so that the resultant Dopplerexperienced by the UE is f_(R)=f_(D)−f_(C), so that the absolute valueof f_(R) is much smaller than that of f_(D) such that it is within thetolerance of the UE receiver, as discussed above. It should beappreciated that the compensation Doppler f_(C) usage is up to the TRPimplementation. For example, it can be used as an initial value and isadjusted when more measurements are obtained from the UE.

As described previously and under reference of FIG. 6, which basicallyillustrates the RAN 1 as discussed in detail above (FIGS. 1 to 4), theDoppler is a function of the relative speed between transmitter andreceiver and hence it is dependent upon the angle between the traindirection and the TRP. As is illustrated in FIG. 6, θ the angle betweenthe direction of travel of the train 4 and the relative directionbetween the train 4 and the TRP 2 e in FIG. 6.

The relative speed is therefore v_(T) cosθ, where v_(T) is the speed ofthe train 4. As can be observed, the speed of the train 4 relative to,for example, the TRP 2 e, i.e. Doppler, changes as the train 4 movesalong track 3. The Doppler would change from very high positive when itis moving towards the TRP to very high negative when it moves away fromthe TRP, such as TRP 2 e. This behavior is also illustrated in FIG. 5,which illustrates a Doppler change of the test scenario in LTE, whereinthe train moves past multiple TRPs (see also TS36.101 mentioned above).

As mentioned, the speed related parameters can include the maximum speedof the train (or the maximum Doppler). This embodiment recognizes thatthe relative speed (i.e. Doppler) changes as the train moves past aserving TRP, e.g. train 4 with UE 5 b passing TRP 2 e, and therefore themaximum speed/Doppler would represent the worst case that theneighboring TRP, e.g. TRP 2 f, would need to prepare to compensate for.This embodiment also recognizes that when the UE performs handover to aneighboring TRP, e.g. UE 5 b performs handover from TRP2 e to TRP 2 f,the angle θ (angle between direction of train and relative direction oftrain with TRP) is likely to be at its smallest value when the targetTRP is furthest away from the train, which would lead to high (orhighest) Doppler between the train and the TRP. The maximumspeed/Doppler would therefore allow the target TRP to use a high Dopplercompensation for the UE that is handing over to it.

In another embodiment, the speed related parameters include an averageabsolute Doppler. The average value can be used by the target TRP as aninitial Doppler compensation after which it can start measuring the UE'sDoppler and adjust accordingly.

In still another embodiment, the speed related parameters also indicatewhether the train is accelerating or slowing down. The acceleration ordeceleration can be indicated, thereby allowing the target TRP to adjustits Doppler compensation accordingly. For example, instead of applyingthe maximum Doppler for the UE, the target TRP can apply the averageDoppler value if it knew the train is slowing down (e.g. when it isclose to a station).

In another embodiment, the UE, e.g. UE 5 b measures its speed, orDoppler, based on the received radio signal from the serving TRP, e.g.TRP 2 e, and signals that speed, or Doppler measurement to the servingTRP.

In another embodiment, the UE measures its speed based on non-radiomeasurements, such as GPS or speedometer, and signals that speed to theserving TRP.

In an embodiment, the serving TRP measures the UE speed, based onmeasurements on the received signal.

In an embodiment, TRPs may be either unidirectional or bidirectional,whereby a unidirectional TRP points in one direction along a lineartrack and a bidirectional TRP points in both directions (forwards andbackwards) along a linear track.

When all TRPs are unidirectional, the signaled speed related parameters,e.g. including the Doppler shift, from the source TRP can be useddirectly by the target TRP (assuming the unidirectional TRPs point inthe same direction).

When all TRPs are bidirectional, the signaled speed related parameters,e.g. including the Doppler shift, from the serving TRP is inverted insign when it is applied by the target TRP (noting that during a handoverbetween bidirectional TRPs, a negative Doppler is observed by the sourceTRP as the train recedes from the source TRP, but a positive Doppler isobserved by the target TRP as the train approaches the target TRP).

When there is a mixed deployment of bidirectional and unidirectionalTRPs, the source TRP indicates whether the signaled speed relatedparameters, e.g. including the Doppler shift, are associated with atrain that is approaching the TRP or a train that is receding from theTRP.

In another embodiment, the high speed train has multiple UEs, forexample the first carriage in the train has a UE 5 a and the lastcarriage in the train has a UE 5 b, as illustrated in FIG. 8. In thiscase, a TRP may compensate for both positive and negative Doppler. Forthe example shown in FIG. 8, the TRP 2 a compensates for positiveDoppler towards UE 5 a (left arrow), since UE 5 a is approaching the TRP2 a, and the TRP 2 a compensates for negative Doppler from UE 5 b, sinceUE 5 b is receding from the TRP 2 a. The TRP 2 a can compensate for bothpositive and negative Doppler by, for example:

1) Assigning some frequency resources to be compensated with positiveDoppler and other frequency resources to be compensated with negativeDoppler. The split between positive and negative Doppler resources canbe semi-static (e.g. through RRC signaling, such as UE specific orsystem information signaling) or dynamic. A guard band may be appliedbetween the positive and negative Doppler resources to controlinterference between the resources.

2) Assigning some time resources (e.g. subframes) to be compensated withpositive Doppler and other time resources to be compensated withnegative Doppler.

3) Segmenting the carrier into component carriers, e.g. according tocarrier aggregation techniques. The component carriers may then haveeither positive or negative Doppler compensation applied to them. Thisallows a single TRP to transmit copies of system information with bothpositive and negative Doppler compensation. The component carriers canbe activated and deactivated as the train passes the TRP. For example,when all UEs of the train are approaching the TRP, all componentcarriers are assigned with positive Doppler compensation; as the trainpasses the TRP, some of the component carriers are switched to operatingwith negative Doppler compensation to support UEs on the train that arereceding from the TRP.

It should be appreciated that the above embodiments relating to thespeed related parameters can be combined such that all the speed relatedparameters discussed above are signaled or only a subset of them issignaled to neighboring TRP(s).

In some embodiments, a train would start from a stationary position andwould accelerate to its desired speed. Hence, the Doppler Effect isexpected to start from a small value and increase as the train movesalong the track. For example, as illustrated in FIG. 9, the train 4stops at the train station 7 and a TRP, such as TRP 2 a, would observevery small Doppler from the train 4. As the train moves away from thetrain station 7, the Doppler would increase, i.e. TRP 2 d would observea larger Doppler than that observed by TRP 2 c, TRP 2 c would observe alarger Doppler than that observed by TRP 2 b and TRP 2 b would observe alarger Doppler than that observed by TRP 2 a.

As mentioned, a UE, e.g. UE 5 a, 5 b, is designed to tolerate up to amaximum Doppler ±f_(UE) and hence Doppler compensation by the TRP is notrequired if it is within the UE tolerance. Recognizing this point, inanother embodiment, a serving TRP will only signal the said speedrelated parameters to its neighboring TRP if the observed absoluteDoppler is above a threshold f_(THRES). Similarly, if a traindecelerates when it is stopping in a station, its absolute Doppler wouldreduce to below the said threshold f_(THRES) and the TRP would not needto report this to the other neighboring TRPs that are closer to thestation 7.

In another embodiment, which pertains to a method 25 for communicationbetween a TRP and a user equipment as illustrated in FIG. 10, thenetwork signals at 26 a speed related parameter including Dopplercompensation to the UE, e.g. UE 5 a and/or 5 b. This can be implementedin the form of broadcast or dedicated signaling. The signaled speedrelated parameter value received at 27 from the UE is used by the UE forits uplink transmission where the UE offsets its frequency by thesignaled Doppler compensation value and thereby compensates for theDoppler effect at 28. The UE would typically assume that the frequencyoffsets in the downlink and uplink are similar and hence, if thedownlink signal is Doppler compensated, then the UE may transmit itsuplink assuming a small frequency offset which results in a largefrequency offset due to the high Doppler at the TRP receiver. Hence,this embodiment reduces the Doppler in the uplink. Moreover, the networkmay only signal speed related parameters, such as a Doppler compensationvalue, to the UE if the observed Doppler from the UE exceeds a thresholdf_(THRES).

In the following, the mobile telecommunications method for atransmission and reception point serving a user equipment, as discussedabove, is explained under reference of FIG. 11.

At 31, a speed related parameter of the served user equipment isobtained, as discussed above. The speed related parameter is indicativeof a Doppler effect, of a maximum speed of the user equipment or thelike, wherein the maximum speed is the maximum speed between atransmission and reception point and the served user equipment. Thespeed related parameter can also be an indicator of an average Dopplerfrequency shift, as discussed above.

At 32, a current speed of the served user equipment is determined, asdiscussed above, such that based on the determined speed, for example,the speed related parameter can be measured. As discussed, the currentspeed can be determined based on a measurement performed by the userequipment, it can be determined based on a radio measurement between theuser equipment and the serving transmission and reception point and itcan be determined based on a location information.

At 33, the speed related parameter of the served user equipment istransmitted to at least one neighboring transmission and receptionpoint.

At 34, compensating for a Doppler effect in a wireless linkcommunication to the served user equipment is based on the measuredspeed related parameter. As discussed, the compensation is further basedon the current speed and the compensation for the Doppler effect caninclude compensation for the Doppler effect in a wireless linkcommunication to the first and second served user equipments, wherein afirst user equipment is located at a first section of a vehicle and asecond user equipment is located at a second section of the vehicle,wherein the first section and the second section are distant from eachother. The Doppler effect compensation may differ for the first andsecond wireless links to the first and second user equipments,respectively, as discussed above, e.g. by applying a negativecompensation to the first user equipment and a positive compensation tothe second user equipment (or vice versa).

As discussed above, the transmission and reception point(s) can beconfigured to communicate in a forward and backward direction along amovement direction of the served user equipment, which is also referredto as bidirectional TRP above or the transmission and reception point(s)can be configured to communicate in one direction along a movementdirection of the served user equipment, which is also referred to asunidirectional TRP above.

Hence, at 35, the Doppler effect compensation for bidirectional TRPs caninclude, as discussed above, the signaling of the speed relatedparameters and inverting the sign of the Doppler shift at the targetTRP. At 36, the Doppler effect compensation for unidirectional TRPs caninclude, as discussed above, the signaling of the speed relatedparameters and the application of the Doppler shift at the target TRPwithout inverting a sign.

At 37, the method 30 can include assigning first frequency resources tothe first user equipment and assigning second frequency resources to thesecond user equipment, wherein the first and second frequency resourcesare Doppler effect compensated, as discussed above. The Doppler effectcompensation for the first and second frequency resources may differ inthe way discussed above, e.g. by applying a negative Doppler shift forthe first frequency resource and a positive Doppler shift for the secondfrequency resources (or vice versa).

At 38, the method 30 can include assigning first time resources to thefirst user equipment and assigning second time resources to the seconduser equipment, wherein the first and second time resources are Dopplereffect compensated, as discussed above, e.g. by applying positiveDoppler effect compensation for the first time resource and negativeDoppler shift compensation to the second time resource, or vice versa.

At 39, the method 30 can include segmenting a carrier into a firstcomponent carrier assigned to the first user equipment and segmentingthe carrier into a second component carrier assigned to the second userequipment, as discussed above, e.g. by applying positive Doppler effectcompensation for the first component carrier and negative Doppler shiftcompensation for the second component carrier, or vice versa.

At 40, the method 30 can include transmitting the speed relatedparameter of the served user equipment to a neighboring transmission andreception point, based on a frequency shift threshold value, asdiscussed above.

In some embodiments, only one of steps 37 to 39 is implemented.Moreover, the ordering of steps 37 to 39 can be freely chosen and theskilled person will adapt it accordingly. Furthermore, only a subset ofsteps 37 to 39 can be implemented in some embodiments, e.g. steps 37 and38, steps 37 and 39, steps 38 and 39, etc.

In the following, an embodiment of a general purpose computer 90 isdescribed under reference of FIG. 12. The computer 90 can be implementedsuch that it can basically function as any type of base station or newradio base station, transmission and reception point, or user equipmentas described herein. The computer has components 91 to 100, which canform a circuitry, such as anyone of the circuitries of the base station,and user equipment, as described herein.

Embodiments which use software, firmware, programs or the like forperforming the methods as described herein can be installed on computer90, which is then configured to be suitable for the concrete embodiment.

The computer 90 has a CPU 91 (Central Processing Unit), which canexecute various types of procedures and methods as described herein, forexample, in accordance with programs stored in a read-only memory (ROM)92, stored in a storage 97 and loaded into a random access memory (RAM)93, stored on a medium 100 which can be inserted in a respective drive99, etc.

The CPU 91, the ROM 92 and the RAM 93 are connected with a bus 101,which in turn is connected to an input/output interface 94. The numberof CPUs, memories and storages is only exemplary, and the skilled personwill appreciate that the computer 90 can be adapted and configuredaccordingly for meeting specific requirements which arise, when itfunctions as a base station, and user equipment.

At the input/output interface 94 several components are connected: aninput 95, an output 96, the storage 97, a communication interface 98 andthe drive 99, into which a medium 100 (compact disc, digital video disc,compact flash memory, or the like) can be inserted.

The input 95 can be a pointer device (mouse, graphic table, or thelike), a keyboard, a microphone, a camera, a touchscreen, etc.

The output 96 can have a display (liquid crystal display, cathode raytube display, light emittance diode display, etc.), loudspeakers, etc.

The storage 97 can have a hard disk, a solid state drive and the like.

The communication interface 98 can be adapted to communicate, forexample, via a local area network (LAN), wireless local area network(WLAN), mobile telecommunications system (GSM, UMTS, LTE, etc.),Bluetooth, infrared, etc.

It should be noted that the description above only pertains to anexample configuration of computer 90. Alternative configurations may beimplemented with additional or other sensors, storage devices,interfaces or the like. For example, the communication interface 98 maysupport other radio access technologies than the mentioned UMTS and LTE.

When the computer 90 functions as a base station, the communicationinterface 98 can further have a respective air interface (providing e.g.E-UTRA protocols OFDMA (downlink) and SC-FDMA (uplink)) and networkinterfaces (implementing for example protocols such as S1-AP, GTP-U,S1-MME, X2-AP, or the like). Moreover, the computer 90 may have one ormore antennas and/or an antenna array. The present disclosure is notlimited to any particularities of such protocols.

The methods as described herein are also implemented in some embodimentsas a computer program causing a computer and/or a processor to performthe method, when being carried out on the computer and/or processor. Insome embodiments, also a non-transitory computer-readable recordingmedium is provided that stores therein a computer program product,which, when executed by a processor, such as the processor describedabove, causes the methods described herein to be performed.

It should be recognized that the embodiments describe methods with anexemplary order of method steps. The specific order of method steps is,however, given for illustrative purposes only and should not beconstrued as binding.

The method can also be implemented as a computer program causing acomputer and/or a processor to perform the method, when being carriedout on the computer and/or processor. In some embodiments, also anon-transitory computer-readable recording medium is provided thatstores therein a computer program product, which, when executed by aprocessor, such as the processor described above, causes the methoddescribed to be performed.

All units and entities described in this specification and claimed inthe appended claims can, if not stated otherwise, be implemented asintegrated circuit logic, for example on a chip, and functionalityprovided by such units and entities can, if not stated otherwise, beimplemented by software.

In so far as the embodiments of the disclosure described above areimplemented, at least in part, using software-controlled data processingapparatus, it will be appreciated that a computer program providing suchsoftware control and a transmission, storage or other medium by whichsuch a computer program is provided are envisaged as aspects of thepresent disclosure.

Note that the present technology can also be configured as describedbelow.

(1) A mobile telecommunications system transmission and reception pointcomprising circuitry configured to:

-   -   receive a status indicator; and    -   switch between an active state and an inactive state in response        to the received status indicator.

(2) The mobile telecommunications system transmission and receptionpoint of (1), wherein the active state includes at least one ofreceiving and transmitting data.

(3) The mobile telecommunications system transmission and receptionpoint of (1) or (2), wherein the inactive state includes at least one ofdiscontinuous reception mode and discontinuous transmission mode.

(4) The mobile telecommunications system transmission and receptionpoint of anyone of (1) to (3), wherein the inactive state includesturning off at least one of a transmitter and receiver.

(5) The mobile telecommunications system transmission and receptionpoint of anyone of (1) to (4), wherein the circuitry is furtherconfigured to transmit a status indicator.

(6) The mobile telecommunications system transmission and receptionpoint of anyone of (1) to (5), wherein the circuitry is furtherconfigured to switch into the inactive state after a predetermined time.

(7) The mobile telecommunications system transmission and receptionpoint of anyone of (1) to (6), wherein the status indicator includes atleast one of: a command to switch in the inactive or active state,connection state information, information about a completed handoverprocedure, end of vehicle information.

(8) A mobile telecommunications system transmission and reception pointcomprising circuitry configured to:

-   -   transmit a status indicator for switching another transmission        and reception point between an active state and an inactive        state.

(9) The mobile telecommunications system transmission and receptionpoint of (8), wherein the circuitry is further configured to transmitthe status indicator to a neighboring transmission and reception point.

(10) The mobile telecommunications system transmission and receptionpoint of (8) or (9), wherein the circuitry is further configured todetect a mobility of a user equipment, the user equipment being mountedto a vehicle.

(11) The mobile telecommunications system transmission and receptionpoint of (10), wherein the vehicle is a train.

(12) The mobile telecommunications system transmission and receptionpoint of (10) or (11), wherein the circuitry is further configured todetect a movement direction of the vehicle.

(13) The mobile telecommunications system transmission and receptionpoint of anyone of (8) to (12), wherein the other transmission andreception point is neighboring to the mobile telecommunications systemtransmission and reception point.

(14) The mobile telecommunications system transmission and receptionpoint of anyone of (10) to (13), wherein the status indicator istransmitted to a number of other transmission and reception points, andthe number of the other transmission and reception points depends on thevelocity of the vehicle.

(15) A mobile telecommunications system base station comprising multipleremote radio heads and circuitry configured to:

-   -   receive a status indicator; and    -   deactivate selectively the multiple remote radio heads based on        the received status indicator.

(16) The mobile telecommunications system base station of (15), whereinthe status indicator is received from a neighboring base station.

(17) The mobile telecommunications system base station of (16), whereindeactivation of the multiple remote radio heads is further based on ageographical relationship to the neighboring base station.

(18) The mobile telecommunications system base station of (16) or (17),wherein the status indicator indicates a last activated remote radiohead of the neighboring base station.

(19) The mobile telecommunications system base station of anyone of (15)to (18), wherein the outermost remote radio heads stay in the activestate.

(20) The mobile telecommunications system base station of anyone of (15)to (19), wherein the circuitry is further configured to detect an activeremote radio head based on a signal measurement.

(21) The mobile telecommunications system base station of (20), whereinthe signal measurement includes at least one of: receiving uplinksignals, sounding reference signals, physical uplink shared channel,ACK/NACK feedback signaling.

(22) The mobile telecommunications system base station of (20) or (21),wherein deactivation of the multiple remote radio heads is further basedon the signal measurement.

(23) The mobile telecommunications system base station of anyone of (20)to (22), wherein the signal measurement is performed by a userequipment.

(24) The mobile telecommunications system base station of anyone of (20)to (23), wherein the remote radio heads are uniquely identifiable.

(25) A mobile telecommunications system method comprising:

-   -   obtaining neighbor cell information including priority        information of neighboring cells to be measured; and    -   measuring cells based on the priority information.

(26) The mobile telecommunications system method of (25), wherein theneighboring cells are located along a direction of a travelling vehicle.

(27) The mobile telecommunications system method of (26), wherein thevehicle is a train.

(28) The mobile telecommunications system method of (26) or (27),wherein the neighboring cell information is indicative of cells forvehicles having different travel directions.

(29) The mobile telecommunications system method of (28), wherein theneighboring cell information is separated for vehicles having differenttravel directions.

(30) The mobile telecommunications system method of anyone of (26) to(29), wherein the neighboring cell information is updated based on thetravelling direction.

(31) The mobile telecommunications system method of anyone of (25) to(30), wherein the neighboring cell information is obtained by aneighboring cell measurement.

(32) The mobile telecommunications system method of (31), wherein a userequipment performs the neighboring cell measurement.

(33) A mobile telecommunications system method for a transmission andreception point serving a user equipment, comprising:

-   -   obtaining a speed related parameter of the served user        equipment; and    -   compensating for a Doppler effect in a wireless link        communication to the served user equipment, based on the        obtained speed related parameter.

(34) The mobile telecommunications system method of (33), wherein thespeed related parameter is indicative of a Doppler effect.

(35) The mobile telecommunications system method (33) or (34), whereinthe speed related parameter is indicative of a maximum speed of the userequipment.

(36) The mobile telecommunications system method of (35), wherein themaximum speed is the maximum speed between a transmission and receptionpoint and the served user equipment.

(37) The mobile telecommunications system method of anyone of (33) to(36), wherein the speed related parameter is an indicator of an averageDoppler frequency shift.

(38) The mobile telecommunications system method of anyone of (33) to(37), further comprising transmitting the speed related parameter of theserved user equipment to at least one neighboring transmission andreception point.

(39) The mobile telecommunications system method of anyone of (33) to(38), further comprising determining a current speed of the served userequipment.

(40) The mobile telecommunications system method of (39), wherein thecompensation is further based on the current speed.

(41) The mobile telecommunications system method of (39) or (40),wherein the current speed is determined based on a measurement performedby the user equipment.

(42) The mobile telecommunications system method of (41), wherein thecurrent speed is determined based on a radio measurement between theuser equipment and the serving transmission and reception point.

(43) The mobile telecommunications system method of (41) or (42),wherein the current speed is determined based on a location information.

(44) The mobile telecommunications system method of anyone of (33) to(43), wherein the transmission and reception point is configured tocommunicate in a forward and backward direction along a movementdirection of the served user equipment.

(45) The mobile telecommunications system method of anyone of (33) to(44), wherein the transmission and reception point is configured tocommunicate in one direction along a movement direction of the serveduser equipment.

(46) The mobile telecommunications system method of anyone of (33) to(45), wherein a first user equipment is located at a first section of avehicle and a second user equipment is located at a second section ofthe vehicle, wherein the first section and the second section aredistant from each other.

(47) The mobile telecommunications system method of (46), whereincompensation for the Doppler effect includes compensation for theDoppler effect in a wireless link communication to the first and secondserved user equipments.

(48) The mobile telecommunications system method of (47), furthercomprising assigning first frequency resources to the first userequipment and assigning second frequency resources to the second userequipment, wherein the first and second frequency resources are Dopplereffect compensated.

(49) The mobile telecommunications system method of (47) or (48),further comprising assigning first time resources to the first userequipment and assigning second time resources to the second userequipment, wherein the first and second time resources are Dopplereffect compensated.

(50) The mobile telecommunications system method of (47), (48) or (49),further comprising segmenting a carrier into a first component carrierassigned to the first user equipment and segmenting the carrier into asecond component carrier assigned to the second user equipment.

(51) The mobile telecommunications system method of anyone of (33) to(50), further comprising transmitting the speed related parameter of theserved user equipment to a neighboring transmission and reception pointbased on a frequency shift threshold value.

(52) The mobile telecommunications system method of anyone of (33) to(51), further comprising transmitting the speed related parameter to theserved user equipment.

(53) A mobile telecommunications system method for a user equipmentserved by a transmission and reception point, comprising:

-   -   receiving a speed related parameter of the served user equipment        form the transmission and reception point; and    -   compensating for a Doppler effect in a wireless link        communication to the transmission and reception point, based on        the obtained speed related parameter.

(54) A computer program comprising program code causing a computer toperform the method according to anyone of (33) to (53), when beingcarried out on a computer.

(55) A non-transitory computer-readable recording medium that storestherein a computer program product, which, when executed by a processor,causes the method according to anyone of (33) to (53) to be performed.

1. A mobile telecommunications system transmission and reception pointcomprising circuitry configured to: receive a status indicator; andswitch between an active state and an inactive state in response to thereceived status indicator.
 2. The mobile telecommunications systemtransmission and reception point of claim 1, wherein the active stateincludes at least one of receiving and transmitting data.
 3. The mobiletelecommunications system transmission and reception point of claim 1,wherein the inactive state includes at least one of discontinuousreception mode and discontinuous transmission mode.
 4. The mobiletelecommunications system transmission and reception point of claim 1,wherein the inactive state includes turning off at least one of atransmitter and receiver.
 5. The mobile telecommunications systemtransmission and reception point of claim 1, wherein the circuitry isfurther configured to transmit a status indicator.
 6. The mobiletelecommunications system transmission and reception point of claim 1,wherein the circuitry is further configured to switch into the inactivestate after a predetermined time.
 7. The mobile telecommunicationssystem transmission and reception point of claim 1, wherein the statusindicator includes at least one of: a command to switch in the inactiveor active state, connection state information, information about acompleted handover procedure, end of vehicle information.
 8. A mobiletelecommunications system transmission and reception point comprisingcircuitry configured to: transmit a status indicator for switchinganother transmission and reception point between an active state and aninactive state.
 9. The mobile telecommunications system transmission andreception point of claim 8, wherein the circuitry is further configuredto transmit the status indicator to a neighboring transmission andreception point.
 10. The mobile telecommunications system transmissionand reception point of claim 8, wherein the circuitry is furtherconfigured to detect a mobility of a user equipment, the user equipmentbeing mounted to a vehicle.
 11. The mobile telecommunications systemtransmission and reception point of claim 10, wherein the vehicle is atrain.
 12. The mobile telecommunications system transmission andreception point of claim 10, wherein the circuitry is further configuredto detect a movement direction of the vehicle.
 13. The mobiletelecommunications system transmission and reception point of claim 8,wherein the other transmission and reception point is neighboring to themobile telecommunications system transmission and reception point. 14.The mobile telecommunications system transmission and reception point ofclaim 10, wherein the status indicator is transmitted to a number ofother transmission and reception points, and the number of the othertransmission and reception points depends on the velocity of thevehicle.
 15. A mobile telecommunications system base station comprisingmultiple remote radio heads and circuitry configured to: receive astatus indicator; and deactivate selectively the multiple remote radioheads based on the received status indicator.
 16. The mobiletelecommunications system base station of claim 15, wherein the statusindicator is received from a neighboring base station.
 17. The mobiletelecommunications system base station of claim 16, wherein deactivationof the multiple remote radio heads is further based on a geographicalrelationship to the neighboring base station.
 18. (canceled)
 19. Themobile telecommunications system base station of claim 15, wherein theoutermost remote radio heads stay in the active state.
 20. The mobiletelecommunications system base station of claim 15, wherein thecircuitry is further configured to detect an active remote radio headbased on a signal measurement. 21.-52. (canceled)
 53. A mobiletelecommunications system method for a user equipment served by atransmission and reception point, comprising: receiving a speed relatedparameter of the served user equipment form the transmission andreception point; and compensating for a Doppler effect in a wirelesslink communication to the transmission and reception point, based on theobtained speed related parameter.